1. Field of the Invention
The present invention relates to construction materials. The present invention is directed toward building components used for building construction and, more particularly, toward a premanufactured, composite building panel or other composite building components that exhibit improved strength, weight, and size characteristics. More particularly, the present invention relates to a synthetic core construction panel and apparatus for making same.
2. Description of Related Art
Recent changes in today""s housing industry have led to an increased use by builders of premanufactured or fabricated construction components. Premanufactured building components, such as panels, are used for walls, roofs, floors, doors, and other components of a building. Premanufactured building components are desirable because they decrease greatly the time and expense involved in constructing new building structures. However, the premanufactured building components must comply with a number of required specifications based on structural criteria, such as axial load-bearing, shear and racking strengths, and total weight of the components. Additional criteria that may affect the specifications of the components include fire resistance, thermal efficiency, acoustical rating, rot and insect resistance, water resistance and hurricane and earthquake resistance. In addition, the preferred premanufactured components are readily transportable, efficiently packaged, and easily handled.
Premanufactured components for building construction have in the past had a variety of constructions. A common component is a laminated or composite panel. One such composite panel includes a core material of foam or other insulating material positioned between wood members, and the combination is fixed together by nails, screws, or adhesives. These wood composite panels suffer from the disadvantage of being combustible and not mechanically stable enough for some construction applications. These wood composite panels are inadequate sound barriers and are subject to rot, decay, and insect attack. Accordingly, wood composite panels are not deemed satisfactory in many modern building applications. In a variation of the wood-composite building panel, a laminated skin is fixed to the outside wood members. These panels with the laminated skin are more expensive to manufacture while suffering from the same inadequacies of the panels without the laminated skin.
More recent prior art efforts have included panels constructed of polystyrene core surrounded by a welded wire mesh. The metal framework of such panels is a three-dimensional wire grille or grating, normally having the form of two parallel meshes joined together by a series of wires welded to them and which hereafter we will call connectors. The lightweight core is a layer of polystyrene, foam resin or dense box material, fiber or plastic, with reinforcing walls and indispensably nonresistant to a segment of wire passing through it. These panels are building elements fitted into the construction as walls or flooring, and are then coated with resistant mortar on both sides; the panels can easily be joined to one another on the building site by conventional means. Known panels of this type are made with very fine wire (2 mm gauge, and mesh opening of 50 mm) and are manufactured according to the following process:
(1) The vertical meshes of the panel are preconstructed in ladderlike form, that is, with two parallel wires between which short cross-members are welded.
(2) These elements are inserted in welding machines in vertical position, and crosswires are welded to them to form the complete spatial structure.
(3) These structures are slightly sunk or imbedded in a sand bed which is made to advance upon a conveyor belt, and a foam resin is sprayed on them to form the lightweight core.
The panels of this type still lack the reinforcement needed for extreme weather conditions. Because the mesh panels are only connected with a series of single spaced thin cross-members, the panel is subject to shearing, with the panels moving in parallel in different directions in response to shearing forces. The prior art panels do not have reinforcing cross-members at all edges, but rather the cross-members are spaced across the mesh faces, including through the core. Apparently, to provide reinforcing cross-members at all edges would require too much xe2x80x9cfinishingxe2x80x9d and would increase the amount of time necessary to construct the panels. The apparati used to make the panels and the methods involved are labor-intensive, cumbersome and slow. There is a need not only for improvements in such panel designs to address hurricane and earthquake resistance needs, but also for a more efficient way of making such panels. This problem is addressed by the present invention through a novel metal grid system resembling a series of interconnected trusses.
The present invention is a synthetic core construction panel and an apparatus for making same. The panels are used as construction materials such as prefabricated wall sections.
The panels themselves in a preferred embodiment have a core made of synthetic material, preferably polyurethane or known substitute materials encased by a metal grid. In a preferred embodiment, the grid system comprises a first series of metal bars disposed parallel to each other, generally equally spaced apart on one face of the panel, said series of metal bars connected to a parallel series of metal bars disposed on the opposite face of the panel by metal bar perpendicular cross-members welded or soldered to the ends of the two series of metal bars to form a generally rectangular grid.
A second series of metal bars, also disposed in parallel to each other, also generally equally spaced apart on one face of the panel, connects to a parallel series of metal bars disposed on the opposite face of the panel by metal bar perpendicular cross-members welded or soldered to the ends of the two series of metal bars. The first series of bars is disposed under the second series of bars or vice versa, such that the two series make contact with the contact points being welded for additional reinforcement.
The metal grid system in a preferred embodiment further comprises a plurality of diagonal cross-member reinforcements welded or soldered at their edges to each connecting point between the first and second series of bars. A space or gap is maintained between the core and the grid and the cross-member reinforcements are partially embedded in the core material. The metal grid serves as a surface accepting masonry/plaster as a finish for the panel after installation. The polyurethane core is fire resistant. The diagonally disposed metal bars keep the polyurethane core centered in place in the panel. The panels are lightweight and extremely strong. The grid system absorbs forces giving the panels utility as earthquake-resistant construction materials. The core can be made of polyurethane or other synthetic materials. The metal used for the grid system can vary.
In a preferred embodiment, construction xe2x80x9cre-barxe2x80x9d is utilized, and the bars are formed into generally rectangular rings by bending, thereby resulting in a grid system with fewer weld or solder points. Various gauges of xe2x80x9cre-barxe2x80x9d can be used. The corners of the generally rectangular rings that are formed are created by bending the xe2x80x9cre-barxe2x80x9d where desired and then welding or soldering the ends together. In this manner, the grid is created by a series of such generally rectangular rings parallel to each other and generally evenly spaced apart, with a second series of generally rectangular rings disposed parallel to each other and generally evenly spaced apart, with the first such series disposed perpendicularly to such second series, with one of the series disposed within the space surrounded by the other series. Where the rings of the two series make contact, the points can be welded or soldered for additional reinforcement. The metal diagonal cross-members are then welded or soldered at various points along the grid formed by the two series of generally rectangular bars. When the liquid form synthetic core is poured into the mold of the apparatus described below, the diagonal cross-members become embedded in the core material, and when the core material dries, the cross-members embedded therein provide additional reinforcement to the panel.
The apparatus of the present invention is a customized hydraulic press injection mold machine. It has a plurality of vertical columns connected to horizontal bars by brackets forming a rectangular box-shaped frame.
Supported within the frame, the machine has two plates that are parallel to each other. In operation the two plates are pressed togetherxe2x80x94the surfaces of each plate that face each other are configured so as to leave a cavity or mold between the two plates into which the polyurethane panel core material can be injected in liquid form. The material takes the form of the mold and hardens over time to become a panel sheet embedded in and reinforced by the metal grid. A gap is maintained between the core and the grid sheets in order to provide a surface that accepts a masonry/plaster finish after the panel has been installed on a building structure.
One of the plates is fixed, being mounted to one side of the apparatus frame. The other plate is moveable, and slides using bushings on upper and lower tracks affixed to the frame. The moveable plate is aligned with the fixed plate so that their inner faces will form a mold when the moveable plate is moved toward the fixed plate.
The moveable plate is connected on the side facing away from the fixed plate to one or more hydraulic cylinder systems, which when actuated press the moveable plate against the fixed plate.
The machine also has a plurality of pneumatic jets that shoot air at high pressure through the plates of the machine after panel material has been injected and has hardened in order to loosen the panel from the mold. The machine also utilizes clamps to hold the plates together as the panel material is injected into the mold cavity and while the material hardens.
As a result, the panels of the present invention can be constructed to vary the load-bearing strength vs. weight characteristics of the building components by varying the thicknesses, densities and configurations of the side panels and the joining sides, and by varying the number and positioning of the shear resistance connectors. Accordingly, a person can design a building structure, determine the structural requirements for the building components, and then select a desired load-bearing strength, shear strength, and weight of the building panels to meet the structural requirements, and then construct the appropriate specified panel required for the defined application.
The improved building components can be very strong, lightweight, and versatile building components. However, the manufacturing of such building components can be a relatively time-consuming and labor-intensive process, which can increase cost and lower availability of the components.